In-plane wireless communication systems are currently being developed to be compatible with modern on-chip technology. Some of the advantages that in-plane wireless communication offers are lower loss and reduction in the number of required waveguides. Most modern on-chip optical technologies use near-infrared wavelengths, but for visible wavelengths, an ideal candidate to perform in-plane communication is the surface plasmon (SP), i.e. the collective oscillation of electrons coupled to an electromagnetic field at a dielectric-metal interface. SPs have the capability to highly confine energy on the interface where they propagate, including to subwavelength scales. An additional property of SPs is their capability to be strongly confined to the surface of metallic structures having subwavelength dimensions, including implementations called plasmonic antennas (PAs). Specially designed PAs can collect free-space radiation (photons) and convert it into propagating surface plasmons (SPs) by a momentum up-conversion process (k-UC). Conversely, PAs can perform a momentum down-conversion process (k-DC) by converting SPs into photons. Several reports have appeared using PAs as receivers or broadcasters of electromagnetic radiation. One limitation of the systems in these reports is that the free-space radiation is emitted predominantly out-of-plane, and little effort has been done to facilitate in-plane emission and collection, i.e., in the direction of the SP propagation. Such an in-plane communication concept could be a significant advancement in on-chip photonic technology, due to better impedance matching between the emitted and received radiation.